Incubation assistance, please.

[Miyu]

Background: over the course of three-four months, we lost half of our chicken flock; on average about one a week. We have now gone a month without any more losses. Our chickens are free range, and we reinforced as best as possible because they are free range. So to replenish the flock, incubation!

10/5: Day one, 8 eggs into a Brinsea incubator, with attached humidifier and auto-turn. Temperature set at 99.4 degrees Fahrenheit and RH% at 45. Cool down was set at one hour, by previous users.
10/6: Day two, four eggs added, to make an even 12.
10/22: Day eighteen, about to go on lock down. I candled four-five days prior, and everything but two eggs looked good, air sacs, veins, etc. Raised the RH to 65% and turned the auto-turn off.
10/25: Day 21, "hatch day". Nada happening
10/26: Day 22, nothing happening.
10/27: Day 23. Nothing happening, but noticed a smell coming from thebincubator, so took the lid off, noticed a pip on the backside of an egg, so quickly put the lid back on. By 4pm, first egg was hatched. Few hours later, another egg had pipped externally.
10/28: Day 24. #2 hatched by morning, and #3 hatched by evening. A fourth egg was pipping externally.
10/29: Day 25. #4 hatched overnight. By afternoon, I moved the hatchlings to a brooder. I float tested the remaining 8 eggs, and all floated with only 10-15% above the water. I then candled them, and only three were dark inside, and I could see a form, though I could not detect movement, I put them back in the incubator. Five duds: I eggtopsied, and two were not fertile. One showed a few days development, one showed perhaps a week of development, and the third appeared to be a fully formed chick that had been squished between two air sacs. It's beak was under the wing, like it was ready to pip, then died.

As far as I know, there weren't major fluctuations in temperature or humidity (aside from candling day). I would check the readings multiple times a day, and make sure the water reservoir had ample water. The only ones I saw were +/- a tenth of a degree of % for RH and +/- 1 degree in temperature, which I assume was from the outside temperature.

My question(s) :
Do I have the cool off period, wrong? Should I calibrate the temperature and RH, to make sure they are accurate ? Because at this point, 4/12 successful hatches, is a bit disappointing. I would like to incubate more, but want to see if I need to fix a problem, that I am not seeing. I am thinking of waiting 24-48 more hours on the three eggs that went back into the incubator, but I don't have my hopes up. Today is Day 25.

Any help would be appreciated. Thank you.

 

[Pyxis]

When you eggtopsied, did you see a lot of liquid? My guess based on what you told us is that your humidity was too high. 45% for the entire first 18 days would drown nearly all the eggs I incubate. I do 30% for the first 18 days. Late deaths are often caused by humidity issues, and it sounds like you mostly had late deaths.

The late hatch also sounds like possible low temps. I would go ahead and calibrate your instruments before the next hatch, to be safe. 99.4 is one point too low (should be 99.5) but that shouldn't cause a hatch to go four days late.

 

[Miyu]

This was my first time at incubating and hatching, so I looked up the manual that goes with this incubator. For humidity in regards to poultry it gave 40-50%, so I went with the middle value of 45%, and during hatching it said 65% or more. For temperature with hens, the range was 99.3-99.6 degrees, again I went with the middle value.

For the eggtopsy, the two that were not fertilized, were all liquid. The two that were not formed, I would guess early death, we're liquid. The fifth, that appeared to be fully formed, there was liquid. Whether or not too much, I'm not sure, as I don't have anything to compare it to.

A number five chick hatched overnight last night.

I will definitely calibrate, to make sure the readings are accurate. Thank you.

 

[Pyxis]

So with the noticeable liquid on the later death chicks, I would say humidity was too high. I'd try 30% next time and see what happens.

Those figures that came with the incubator are meant to be guidelines and unfortunately they don't work for some people. What you need to use is affected by your elevation, local climate, etc. While the temp readings they provided wouldn't cause the eggs not to hatch, 99.5 is known to be the ideal temp. Lower can cause late hatches.

Definitely calibrate and make sure the readings are correct. Hopefully you will have better luck next time!

 

[Mak24456]

To add on to what Pyxis said - humidity is definitely different for everyone. For my first and latest hatch, I kept humidity in the 30s for the first 18 days but the air cells turned out too big. If I ever hatch again, I'll keep it in the 40s. The only way to really know what your humidity should be is to play around with it, so I'd also recommend going slightly lower.

Your main problem seems to be with the incubator's reading, calibrate and make adjustments to have it at 99.5
I don't know if brinsea actually makes still air incubators, but if it is still air then 102 is recommended.